Environmental tobacco smoke (ETS) exposure has been identified as a significant threat to children's respiratory health and has been clearly linked to increased risk of asthma, bronchitis, wheeze and otitis media. ETS exposure is higher in households at or below poverty level and this same population has also been found to be at significantly increased risk for asthma morbidity, as well as other respiratory infections. Studies have reported that between 30-70% of low-income children with asthma enrolled in Head Start programs report a smoker in the home. Because of the increased health risks experienced by their students, Head Start programs have a mandate to help high-risk families improve the health of their preschool children. Further, in 2007 the Environmental Protection Agency (EPA) and the Office of Head Start announced a new initiative to promote smoke-free homes for Head Start Children. For these reasons, Head Start programs offer a timely and important venue for reaching high-risk, low-income pre-school children and intervening to reduce these children's exposure to ETS. We therefore propose to draw on our established health and research partnership with Head Start programs in Baltimore City to test the effectiveness of an ETS reduction intervention with demonstrated efficacy, when delivered in the context of an overall EPA-based Head Start ETS reduction education program. Specifically, we will conduct a randomized clinical trial of a home-delivered, motivational interviewing-based ETS reduction intervention combined with a HS-level EPA/ETS education program in reducing children's ETS exposure, compared to a HS-level EPA/ETS education program alone. We will enroll 350 HS students aged 2-5 years with a caregiver-reported smoker in the home from all 17 Baltimore City HS programs. The primary study outcome measure will be household ETS levels, as measured by home air nicotine levels at six month follow-up. Secondary outcomes include caregiver-reported home and car smoking bans, child's salivary cotinine levels, children's respiratory symptoms, caregiver smoking cessation, school absences, and health care utilization measures. In addition, at the HS level we will evaluate the degree of implementation of the HS-level EPA/ETS education program, change in the proportion of families who report smoking in home for all HS students, and change in HS staff knowledge, attitudes and practices related to ETS exposure and reduction. If successful, this demonstration and education project could have significant public health implications for school and community-based strategies to improve children's long-term respiratory health. Environmental tobacco smoke (ETS) exposure has been identified as a significant threat to children's respiratory health and has been clearly linked to increased risk of asthma, bronchitis, wheeze and otitis media. Low-income and minority children are more likely to be exposed to second-hand smoke and to suffer respiratory illnesses, such as asthma. The current study will test a behavioral intervention to reduce ETS exposure among low-income preschool children enrolled in Head Start and if successful, this project could have significant public health implications for school and community-based strategies to improve children's long-term respiratory health.